/* FCE Ultra - NES/Famicom Emulator
 *
 * Copyright notice for this file:
 *  Copyright (C) 2002 Xodnizel
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include "mapinc.h"

//16 bits of ram in total
//only use bottom 4 bits as ram though
static uint8 mapper228_ram[4];

static SFORMAT StateRegs[] =
{
	{ mapper228_ram, 4, "MRAM" },
	{ 0 }
};

static DECLFR(Mapper228_read) {
	return mapper228_ram[A & 3] & 0xF;
}

static DECLFW(Mapper228_write) {
	uint32 page, pagel, pageh;

	//write to ram
	if (A < 0x6000) {
		mapper228_ram[A & 3] = V;
		return;
	}
	MIRROR_SET((A >> 13) & 1);
	page = (A >> 7) & 0x3F;

	if ((page & 0x30) == 0x30)
		page -= 0x10;

	pagel = pageh = (page << 1) + (((A >> 6) & 1) & ((A >> 5) & 1));
	pageh += ((A >> 5) & 1) ^ 1;

	ROM_BANK16(0x8000, pagel);
	ROM_BANK16(0xC000, pageh);
	VROM_BANK8((V & 0x3) | ((A & 0xF) << 2));
}

static void A52Reset(void) {
	Mapper228_write(0x8000, 0);
}

void Mapper228_init(void) {
	MapperReset = A52Reset;
	A52Reset();
	SetWriteHandler(0x8000, 0xFFFF, Mapper228_write);
	SetWriteHandler(0x4020, 0x5FFF, Mapper228_write);
	SetReadHandler(0x4020, 0x5FFF, Mapper228_read);
	AddExState(StateRegs, ~0, 0, 0);
}

